1. Field of the Invention
The present invention relates to a reciprocating internal combustion engine with a wet cylinder sleeve.
2. Description of the Prior Art
A cylinder sleeve, around which the coolant flows only in the upper portion, is disclosed in German Offenlegungsschrift No. 20 30 983. In this device, the lower portion of the cylinder sleeve is inserted into a cylindrical receptacle, the cylinder sleeve and the receptacle being adjacent each other over the entire length of the receptacle. No space is formed therebetween. This arrangement has the disadvantage that the cylinder sleeve has an unfavorable temperature pattern over its length. The upper portion of the cylinder sleeve which is subjected to particularly high heat stress (near the combustion chamber) is cooled too slowly, since at that point the cylinder sleeve has a large wall thickness. The device also has the disadvantage of unnecessary weight. Furthermore, the space towards the cylinder head, which extends between the cylinder crank housing and the cylinder sleeve, and which contains the coolant, is very small so that the volume of coolant present in this region does not give a satisfactory cooling effect. Furthermore, owing to the contact between the receptacle and the cylinder sleeve, the lower portion of the cylinder sleeve, which is typically colder, cools quickly when the reciprocating internal combustion engine is operating. During cold starts, it warms too slowly. On account of this slow heating of the lower portion of the cylinder sleeve, the ignition flame is extinguished (flame blow-out effect). This is particularly the case in the lower load range of operation of the internal combustion engine and results in an increased hydrocarbon emission.